Compressor project(s)

[Gareth J]

I was asking a while back for giant compressors for a tractor driven project. Once again, eBay provided.

Got a huge, 15hp 6" stroke 5" bore, twin water cooled broom &wade in need of some fixing and a smaller one that might suit my workshop.

Tractor project is on hold as a local chap is interested in the big one as a unit if I can get it going.

It needs two unloader valve caps fixing.

They are both broken like this. The crack includes part of the internal surface which houses a brass, 1.75" piston.

They fit onto here;

I've been ringing/emailing companies today who have almost all come back to me with no spares available (still waiting on two, fingers crossed)

So I'm thinking I'll have to work around it and think of a way to remake them.

I could have a go at machining from scratch, probably make it in two parts with the flange loose - like a motorbike exhaust clamp. But that's a fair bit if work, some tool buying and a lot of learning before I can manage that.

My other thought was to weld them up (have already had a go on one and it seems like it might be mechanically strong enough. Then, bore out the inside a few mm oversize and fit a liner. There seems to be enough metal in the thing. But I don't know where I can gat a 1.75" liner from...

Any other suggestions?

Could I do away with them all together?

 

[penfold]

There's nowt magic about liners; why not have a go at making one? Classic car brake renovators might have liners on the shelf that kind of diameter; alloy slave cylinders and calipers often end up being sleeved if new ones are unobtanium.

 

[Gareth J]

Yes, its looking more and more like I will have to make them.

I thought liners might be good as they'd save me sourcing a chunk of sensible material and should be machined to a good tolerance. Will look around for brake refurbishers, that's a good suggestion.

But I'm now increasingly thinking they can be ditched too, they seem to allow the compressor to "blow off" when up to pressure. Fine if it was running more often than not but the chap who's interested would be looking at using an electrical cut in/out like on a small compressor anyway

 

[AndyStobbs]

Wired to his pto clutch?

 

[Gareth J]

Sorry, no. The PTO project was my own. The other chap is keen for a big compressor running on 3 phase. I don't mind moving it on as a complete unit and postponing mobile compressors for another day.

 

[Gareth J]

Update;
Have been refurbishing my 3kW single phase motor. Had to build up the bearing surfaces with weld and machine back as they were very sloppy. New bearings and seals and a coat of paint and it's coming together nicely. I'm not sure it'll be man enough yet but I'm going to give it a try. I can gear down with a small pulley to the minimum rpm the compressor can be run at. I found this suggestion of 460rpm on another forum after a bit of googling. It is kind of working with third hand information but I have nothing else to go with. Didn't ought to go much less as the oil pump system may struggle..?

Anyway, back to the motor. It's all reassembled and rolling free and I'd like to test it works before I buy the pulley. Any ideas on wiring? I have 3 capacitors, two together and 1 solo. I'm pretty sure the motor was working and they are wired as below:

And it looks like there are 6 wires coming from the motor.

I tried plumping for:
bottom right; neutral
top left; brown

But that popped a fuse almost instantly.

Any suggestions?

 

[Maker]

It sounds like a the phase motor to me, with the capacitors functioning as a static phase converter. If so then there should be bars on some of the terminals to change the motor from star to delta, aka 415 to 230. Doubleboost has a recent video about it.

 

[Gareth J]

It sounds like a the phase motor to me, with the capacitors functioning as a static phase converter. If so then there should be bars on some of the terminals to change the motor from star to delta, aka 415 to 230. Doubleboost has a recent video about it.

Hmm, not sure. I thought that to start with but the brass plate definitely says single phase and inside the motor is a centrifugal clutch that presumably fires the start capacitor/s. I don't think it'd have that if it was a 3 phase originally.

Maybe the 3pg version is more or less the same but the factory add caps and a start switch

 

[eil]

Try connecting your live and neutral to U1 and U2. A better pic would help though.

 

[Gareth J]

Try connecting your live and neutral to U1 and U2. A better pic would help though.

Yea, ok, that's a fair comment. Looks a bit clearer here.

And here's a wiring diagram based on what I thing is going on after a play with my multimeter.

NOTE: top solid bar isn't there.

NOTE: top solid bar isn't there.

There is one wire labeled as U1.
The two orange wires are open circuit but I think they may be to do with the starting clutch device.

So one wire to U1 (top right) and the other to middle right?

Cheers

(Edited, got my left/right muddled!)

 

[Gareth J]

Got it, found another label. U1 and U2 as suggested. Purring like a kitten. Thanks

 

[Gareth J]

So, onwards to the next hurdle. I've pulled the old 3pg motor off the base and been looking at the pump. It's pretty big, I hope I have enough horsies to spin it.

There's a little fitting on the back of the pump that when turned by hand, starts pumping out oil. It's in this PIC:

Right in the middle above the crank end cap.

For an oil pressure gauge? Or plumbed away somewhere else?

Anyone know this unit? It's a "H41 A"

 

[Gareth J]

Got distracted here too:
http://www.britishpathe.com/video/broomwade-presents-reel-1
Too easy to spend time on that site

 

[penfold]

It's presumably an oil feed for something, although my booze-addled mind can't think what.

 

[brianblock]

its where the sight glass goes (notice how its level with where you check the oil level )

 

[Gareth J]

It's presumably an oil feed for something, although my booze-addled mind can't think what.

Yea, that's what I'm thinking. Unless it's just a take off for a pressure gauge. Let me know if anything comes to you in the cold light of day. I'll phone the chap I bought it off later, he was pretty clueless but might remember something.

its where the sight glass goes (notice how its level with where you check the oil level )

Naah, the dipstick is for that. Oil level is way down in the sump!

 

[Wendelspanswick]

Yea, that's what I'm thinking. Unless it's just a take off for a pressure gauge. Let me know if anything comes to you in the cold light of day. I'll phone the chap I bought it off later, he was pretty clueless but might remember something.



Naah, the dipstick is for that. Oil level is way down in the sump!

It could be just a breather for the crankcase, piped into the air filter.

 

[Rig Pig]

Oil pressure gauge

 

[Gareth J]

Oil pressure gauge View attachment 64865

Winner!

Thanks so much. That looks veeery similar to my unit, even the folded sheet steel base it's bolted to.

At least I can block it off for now until I can find a replacement. Thanks again!

 

[normspanners]

Just thought i would post this looks like this one oil feed has been used to work the unloader so that it doesnt produce air till motor has oil pressure ?